var gulp = require('gulp');
var postcss = require('gulp-postcss');
var px2rem = require('postcss-px2rem');

// 应用 PostCSS 插件
gulp.task('css', function() {
    var processors = [px2rem({remUnit: 75})];
    return gulp.src('www/css/main.css')
      .pipe(postcss([
        px2rem({remUnit: 75}),
        require('autoprefixer')({
            "browsers": ["iOS 7", "Android >= 4.0"]
        }),
        require('cssnano')({
          reduceIdents: false
        })
      ]))
      .pipe(gulp.dest('www/dest'));
  });